All you have to do is take a look at people who suddenly get rich to understand Picard' point of view. Man will grow and change and so will his understanding of the universe. He will have the experience to use the power with wisdom.
Look at Riker, already thinking he knows what people want. How long before he would've began to enforce it on them? All you have to do is look to Gary Mitchell and Charlie Evans to understand the point that Roddenberry was trying to get across.
Where No Man... wrote:
KIRK: You were a psychiatrist once. You know the ugly, savage things we all keep buried, that none of us dare expose. But he'll dare. Who's to stop him? He doesn't need to care. Be a psychiatrist for one minute longer. What do you see happening to him? What's your prognosis, Doctor?
Hide and Q wrote:
PICARD: And have you noticed how you and I are now on a first name basis?